Drill grinding machine



Nov. 2, 1948. w. uMBDENsTocK 1 2,452,703

DRILL GRINDING MACHINE Filed Dec. 1 8, 1944 6 Sheets-Sheet 1 Nov. 2,194s.

w. UMBDENsTocK 2,452,703

DRILL GRINDING MACHINE Filed Deo. 1s, 1944 e sheets-sheet 2 NOV- 2,1948l w. UMBDENsTocK l 2,452,703

DRILL GRINDING MACHINE lFiled Dec. 18, 1944 6 Sheets-Sheet 3 .I l I I ll i i Nov. 2, 1948. w. uMBDENsTocK I DRILL GRINDING MACHINE ve;sheets-'sheet 4 Filed DeG. 18, 1944 gwn@ w, a@

Crt

1 F I I Il Nov. 2, 1948. w. uMBDENs-rocK DRILL GRINDING MACHINE 6Sheets-Sheet 5 Filed Dec. 18, 1944 u@ @XF w# 6 Sheetsl-Sheet 6 l W.UMBDENSTOCK DRILL GRINDING MACHINE Nov. z, 1948.l

Filved Dec. 18. 1944 Patented Nov. 2, 1948 UNITED STATES PATENT oFFlcEDRILL GRINDING MACHINE Walter Umbdenstock, Chicago, Ill., assignor toLion Manufacturing Corporation, Chicago, Ill., a corporation of IllinoisApplication December 18, 1944, Serial No. 568,608

17 Claims.

The present invention relates in general to grinding machines and hasmore particular reference to machines for grinding drills.

An important object of the invention is to provvide a grinding machinepartlcularly adapted for grinding heli-cal lands, as at the cutting edgeof a drill.

Another important object is to provide a grinding machine adapted forgrinding stepped drills.

A further object is to provide a grinding machine having coordinatedmeans for feeding a work piece toward a grinding wheel in rhythmicfashion whereby to form a land in the work piece as along the cuttingedge of a drill; a further object being to coordinate the rhythmicmovement of the work piece with its longitudinal movement with respectto the grinding member in order to form the cut land to a desiredhelical shape.

Another object is to provide a work holding chuck for rotating a workpiece with respect to a grinding element or wheel and having means forreciprocating the work piece in an aXial direction and also in adirection laterally of the work piece whereby to present the same to agrinding member in rhythmic reciprocation in a plurality of directionsto allow for the grinding of helical lands and shoulders in the workpiece; a further obj ect being to provide correlated means forcontrolling the axial and lateral reciprocating l movement in timedrelation the one with respect to the other, and with respect to therotary movement of the work piece.

Another object is to provide suitable means for reciprocating the workpiece in timed relation with its rotation and to utilize a springactuated rotary cam to that end.

Another object is to provide suitable means for moving the work piecerhythmically in timed relation with its rotation and to utilize magneticmeans to that end. the magnetic means being energized under the controlof timer mechanism driven in timed relation with the work piece toreciprocate the same.

Another important object is to provide suitable timer mechanism forcontrolling the reciprocation of the work piece in timed relation withits rotation. These and numerous other important objects, advantages andinherent functions of the invention will become apparent as theinvention is more fully understood from the following description,which, taken in conjunction with the accompanying drawings, discloses apreferred embodiment of the invention.

Referring to the drawings:

Fig. 1 is a top plan view of a grinding machine embodying the presentinvention;

Fig. 2 is a front view of the machine shown in Fig. 1;

Fig. 3 is an end view of the machine shown vin Figs. 1 and 2;

Figs. 4 and 5 are sectional views, respectively, taken substantiallyalong the lines 4-4 and 5 5 in Figs. 1 and 2;

Fig. 6 is a back View of the structure shown in Fig. 5;

Fig. 'lis a sectional view taken substantially along the line 1-1 inFig. 1;

Fig. 8 is a sectional view taken substantially along the line 3 8 inFig. 7;

Fig. 9 is a sectional view taken substantially along the line 9-9 inFig. 2; and

Fig. 10 is a sectional View taken substantiall along the line Ill-I0 inFig. 9.

To illustrate the invention the drawings show a drill grinding machineparticularly adapted for grinding helical lands as along the leading orcutting edge of drills and adapted also for the forminny of steppeddrills, that is to say, drills having cuttings tips of relatively smalldiameter and cutting bodies of larger diameter adjacent-and behind thetip, and having cutting shoulders extending between the tip and thebody. It should be understood, of course, that a stepped drill may haveone or more shoulders and two or more drilling portions of unlikediameter.

g As shown in the drawings, the grinding machine affords means f'orpresenting a work piece lI, comprising a drill, in position to be groundby a grinding element comprising a grinding wheel I3.

The work piece as shown more particularly in Figs. 7 and 8 may comprisea cylindrical stem having two or more helical grooves I5 cut in the endof the stem, leaving helical utes I'I between the grooves I5.

' By projecting and retracting the work piece laterally toward and -awayfrom the grinding wheel, during each rotation, and by properly timingthe movement so that `grinding engagement of the work piece and grindingWheel may take place just after the leading edge of a flute, duringrotation of the work piece, has `cleared the grinding wheel, thematerial at the surface of the ute may be ground away as. shown at I9,leaving a land 2l at sai-dleading edge of the flute. Of course, thegrinding machine will be arranged to project and retract the work pieceas many times during one revolutionof the work piece as there are fluteson the drill, the piece being projected in proper timed relationship toallow for the formation of the lands, and 'being retracted during theperiod when a groove l5 is facing the grinding wheel.

The projection and retraction of the work piece in forming the lands 2|by undercutting the flute surfaces from the trailing edgesV of the landstoY the trailing edges of the iiutes, may also be -controlled so as toincrease the depth of the undercutting I9 toward the trailing edges `ofthe flutes. The ground away, or undercut portion-s I9 may thus uniformlyand progressively increase in depth from the lands 2| toward thetrailing edges of the flutes I1.

In the fabrication of a stepped drill, that is to say, a drill having atip of relatively small diameter and a body of larger cutting diameteradjacent the tip, there will be a shoulder 23V in each -of flutes I'joining the flute portions forming the drill body, with the fluteportions of lesser diameter forming 'the drill tip. By reciprocating thework -piece axially during the grinding operation, the surfaces of theseshoulders may be given a helical -screw configuration in order` thatthe' leading edge. 25 ofxthese shoulders may form a cutting edge. Theshoulder forming surfaces 2:3 also may be joined to the ute surfaces ofthe drill 'tip by means 4of a rounded fillet to thereby strengthen thetip Iportion and avoid the formation of burrs in holes drilled by thefinished drill, at the step therein. To this end, the work pie-ce may bereciprocated axially, in timed relationship with its rotation, toretract the work piece to a maximum extent during the period when agroove l5 is opposite the grinding wheel.

The work piece may be progressively projected toward the grinding wheelwhile a flute Il is turning lagainst the wheel so that the shoulder maybe cut in the flute and inclined in the drill so that itsY trailing edge21 is offset behind its leading edge in a direction away from thecutting end or tip of the drill.

Furthermore, by correlating the lateral with d the axial movement of thework piece in timed relationship the one with respect to the other, theYshoulder 2'3 Vmay be given 'a twisted configuration in which the outerportions 29 of the shoulder are offset with respect to the innerportions 3l in a direction away Yfrom the tip of the drill, and said-outer portions 29 may be offset with respect to the inner portions 3|to a greater degree adjacent the trailing edge 2'! `than in the shoulderportions adjacent the leading edge 25.

In 4order to provide for drill grinding in the manner described, thegrinding machine of the present invention comprises a suitable base 33forming la mounting for the grinding wheel I3 and a sliding frame 35,which is movable on the frame 33 toward and awayI from the grindingwheel I3' in response to manual operation ,of a. hand wheel 3.1. The.sliding frame `or carriage Ssupports a chuck 39 having facilities `forsupporting ,the workpiece ll in position .for grinding against the wheelI3. Ilhe carriage 35 also supports a drive motor. 4l .and gear .train43. through which the motor .is connected to rotate thewchuck 39 andthevwork piece Il, sothat the samemay be presented t-o the grindingwheel and rotated during the grinding operation.

The ychuck is lprovided withmeans including a cam 45 for reciprocatingthe same and the work piece. in 'a direction axially thereof, and` meansincluding an armature H5 and an eletlrmagf net 41 is also provided formoving the chuck and work piece laterally toward and away from thegrinding wheel while the work piece is being rotated in grindingposition. As shown, the reciprocating means 45 `comprises a cam, whilethe means 4'! embodies a magnet energized under the control `of a timermechanism d'9, which is driven from the motor 4l and hence functions intimed relationshipwith the turning movement of the work piece. Thegrinding machine includes facilities for rotatably `adjusting the cam 45as well as the timing mechanism 49 so that the axial andlateral movementof the work piece may take place as a timed function of the rotation ofthe work piece, that is to say, by adjusting the cam, the projection andretraction of the work piece in an laxial direction may be timed to takeplace at denite predetermined intervals during each revolution of thework piece. Likewise, the timing .mechanism 49 may be adjusted to -causelateral projection and retraction of the work piece toward and away fromthe grinding Wheel at desired intervals during its rotation. The timing`mechanism further includes facilities, in'- dicated generally at 5i,automatically `causing the advancement or retardation of the timer asthe carriage 35 is moved on the main lframe to carry the work pieceacross the grinding wheel. This causes the work piece, as it is movedaxially, 'co-project toward and to retract from the grinding wheel atthe proper instant 'so that the lands 2l may lbe cut helically along theedges of the helical utes I1.

The support frame or base The base 33 on which the grinding machine ismounted preferably comprises an elongated bed plate 53, having dependinglateral walls 55, and

supported on suitable legs El. Bed plate 53, in its upper surface, isformed with grcoves 59 and 6i for receiving corresponding ribs 93 andformed on the under surface of the carriage 35. The carriage 35comprises a plate-like block adapted to support the chuck 39, the motor4l, the transmission 43, and the timer 49. The carriage 35 at itsunderside carries a longitudinally extending rack 6i, which extendsdownwardly of the carriage in a slot`69 formed in the bed plate 53. rEherack Si is drivingly connected with a gear 'ii carried on a shaft i3,the opposite ends of which are supported in bearings 'i5 formed on andextending inwardly of the lateral walls of the base. An end of the shaft13 extends outwardly of the wall 55 at the front of the base and carriesa hand wheel 3'? thereon so that by turning the hand wheel thecarriageli may be moved in either direction along the tcp of the bedplate, through the action of the gear 'il and the rack Si.

The grinder head The grinding wheel i3 is supported in a head ifi, whichprovides bearings i9 for a shaft 8l on which the wheel is mounted. Thehead 'i'i prou vides support for a motor 83, which is connected to drivethe shaft 8l as by means of suitable pulleys drivingly connected by abelt 85. The bearings 19 are secured together in a bracket i3@-rotatably mounted in the head ii and secured in adjusted position by thebolts 13 passing through the arcuate slots 'i8a (see Fig. 2). The headalso is supported ina carriage movable transversely of the frame underthe control of a suitable hand wheel .carried on a shaft extendingthrough and supported bythe Awalls 55A The work head The chuck 39 iscarried on a work head 81 comprisinga block 89 formed with a cylindricalopening 9| in which the chuck extends. The block is formed with a baseplate 93 and is suitably supported upon spaced pedestals 95, which inturn are mounted on the carriage 36, suitable bearings 91 being providedfor supporting' the plate 93 on the pedestals 95 for rocking movementabout an axis parallel to the axis of the chuck.

The base plate 93 has an extension 99 projecting on one side of the workhead in position to overlie a stop screw threaded in a mounting |03 onthe carriage 35 and thus adapted to form -an adjustable stop forlimiting the rocking movement of the head in one direction about theaxis of the bearings 91. The block 89 is provided with a ilange |05extending therefrom on the side of the bearings 91 opposite from theextension 99 in position to overlie adjustable stop means for limitingthe rocking movement of the head in the opposite direction about theaxis of the bearings 91, said stop means comprising a pedestal |01 onthe carriage 35 and a bolt |09 adjustably threaded in the pedestal inposition to extend beneath the flange |05. A pair of springs Il isprovided in position, between the carriage 35 and the flange |05, tonormally urge the head on the pivots 91 in a direction to engage theextension 99 with the stop the head being movable about the pivots 51,in the opposite direction against the influence of the springs i,through an angular distance limited by the engagement of the ilange |95with the stop |09. Spring tension may be adjusted by means of theadjustable screws |53 mounted in the ange and forming mountings for theends of the springs.

In order to move the head against the inuence of the springs thecarriage supports" the velectromagnet 41 in position beneath the ange|05 to cooperate with an armature piece 5 on the flange so that wheneverthe magnet is electrically energized, the head will be rocked from theposition illustrated more particularly in Fig. 5, to a i position inwhich the nange |05 engages the stop |09.

The chuck 39 comprises a stem ||1 having an axial cavity H9 at one endin which is received a split friction clutch element, |2i. This clutchelement is adapted to receive the work piece i i and to frictionallygrip and secure the same to the stern 1. The clutch element i2! is heldagainst rotation with respect to the stem H'lby means of a key |23, inthe stem H1, and forms a splined connection with the clutch element. Theclutch element is held in the cavity Il@ by a gland |25 threaded uponthe end of the stem ||1 having the cavity H9, said end projectingoutwardly of the block 89. By tightening the gland |25 upon the threadedend of the stem the clutch velement l2! is forced axially into thecavity H9 and is caused to bin-dingly grip a work piece therein by theinteraction of cam surface |21 in the cavity ||9 at the end of the stemH1 and on the outer surface of the split clutch element. The stem H1 issupported in suitable bearings |29 located in thehead at the oppositeends of the channel 9|. The projecting socketed end of the stem ||1 isprovided with an outstanding flange |3| forming a support for a thrustbearing |33 carried in and supported on one side by a mounting |35. Theother side of the thrust bearing |33 engages a spring E31 mounted in theend of the head so that the chuck 39 is normally urged by the spring |31in a direction to project tne chuck and work piece axially of the head.Movement of the chuck under the influence of the spring, however, islimited by the engagement of a flange |39 formed on the stem i i1 inposition to engage the end of the block 09 remote from the spring |31.Ti iiange |39 forms a raceway for roller bearing means |4| forming athrust bearing for the stem i |1. outwardly of the bearing 55| the stemcarries a collar 53 having a head forming the cam 45, said cam beingformed in the surface of the head which faces the end of the block 89.

The block 89 at its end adjacent the cam 45 carries a mounting for a camfollowing roller carried in a manually operable bell crank for advancingand retracting the cam following roller with respect to the cam 45. Whenthe roller is retracted from the cam, the same is inactive and the stem||1 may rotate in the block 89 on the bearing |4| under the inuence ofthe spring |31. When, however, the cam follower |45 is projected, thecam will be active and rotation of the stem will impart longitudinalmovement in accordance with the shape of the cam. The cam is formed withprojections |41 at spaced intervals so that the stem ||1 will be drawnor retracted axially whenever a projection encounters the camkfollowingroller |45. Where the work piece is formed with two drill grooves i5,the cam 45 may be provided with a Apair of diametrically oppositeprojections |41 at an angular position with respect to the stem so thatthe stem may be retracted during the intervals when the grinding wheelis opposite the grooves l5 in order that the drill may be formed withthe inclined shoulder 3| heretofore described. Since the shoulder 3| isformed at a particular Zone in the drill, it is not necessary to providefor the automatic adjustmentvof the cam 45 angularly with respect to thestem. However, means is provided for adjusting the cam 45 angularly inorder to locate the projections at a required position to adjust themechanism to a particular work piece in the chuck This is accomplishedby fastening the collar |43 on the stem |1 by means of one or more setscrews |49, adjustment being facilitated by a hand knob |5| screwed onthe projecting end of the stem ||1 adjacent to the collar |43.

The stem |1 also is formed with a slot or cavity |53 in position withinthe block 89 to receive a locking stud |55 carried on a stem which isaxially movable in a, bushing |51 mounted on the block 89. The lockingstud is yieldingly urged, as by means of a spring |59, in a direction tonormally engage the stud ||5 in the cavity |53 to thereby hold the stem|1 against rotation to facilitate in setting up the equipment forgrinding a work piece. The stud |55, however, may be retracted againstthe iniluence of the spring by means of a handle |6| on the stem andlatched in retracted position by means of a latching stud |63. i

v The collar |43 carries an annular gear |65 xed thereon, said gearbeing in position to drivingly engage a pinion |51 forming a part of thetransmission 43 through which the motor 4| Yis drivingly connected toturn the chuck 39.

The transmission 43 comprises a drive shaft |69 carrying the pinion |61and a gear |1| which is drivingly connected in turn `with a gear |13 onthe shaft of the motor 4|. v

The shaft |69 is journaled insuitable bearings |15 and |11 on thecarriage. 35, and the motor 4| may be supported on a bracket |19 whichis also mounted on the carriage 35.

'wheel during the rotation of operation. of a ,switch opening cam |85.

:amamos The ltimer 'mechanism' In order to advance and retract the workpiece laterally toward and away from the grinding wheel |,3 whereby tocut the lands 2| in the work piece, means is provided for energizing themagnet 41- so as to rock the work head in a direction on Iits pivots 91to engage the work piece with the vgrinding wheel at the instant whenthe land portion of the work piece has cleared the grinding the saidpiece. As the work piece is advanced axially with respect `tothe-grinding wheel by Ithe'manipulation of the hand wheel 3,1, it willbe seen that the actuation wofi theV inagn'et'will have to be advancedor retarded, as-.the case may be, so that the lands 2| maybe cut inconformity. with the helical congurationgrooves |5 in the work piece. Tothis endactuation` of the magnet is controlled by the timer mechanism49-4 which comprises a switch |i3|v electrically connected in theenergizing circuitofthemagnet 4.1.v Thevswitch |8|-is normally closed asby means ofl a` spring |83- but may-be `opened against-the inuence ofthe spring by the This cam is driven in timed relation with the rotationofthe work piece so as to'ener-gizethe magnet during the periodsrequiredfor cutting the lands y2,|. The camalso may be adapted to actuate the`switch one or more times for each rotation of the f cam depending uponthe ratioof the gear trains dr-ivingthe cam and the work piece. If thecam .andwork piece be driven at the same speed, the `cam will bedesigned to actuate the kswitch as vmany times during each rotation of.the cam as there are grooves |5 in the work piece. If. there` be twogrooves |.5 in the-workpiece and the cam |85 be driven at t-wotimesthespeed of the work piece,

then thecamwill necessarily be designed to actuate `the switch oncekduring each rotation of theca-m.

As shown more particularly in Fig.. 10, the cam |-85-is adapted'to opentheswitch |83 two times during each rotation of the cam which is to saythat, kin the embodiment illustrated wherein the workpiece contains twogrooves L5, the cam |85 and workpiece ,arey driven at the same speed ofrotation.

The switch |81 is supported in va preferably shell-like casingcomprising a cup-like cover 1.8.1 mounted at its edges upon a supportingdisc |89 having a central hub |.9l formed with. a central opening andthreaded upon a shaft |93. The shaft |93'is rotatably supported inbearings |95 which. in turn are mountedin pedestals |91 supportedv onthe carriage 35.

The cam |85 is fastened' upon an end of a cam driving stem |99 extendingwithinthe cover |81 in position to actuate the switch. The stem |99 isiournaled in a bearing 29| mounted in the hub` |9|`, and extends thencethrough an 'axial bore 293 lin thefsh'aftl |93, the stem |99 projectingatlthe end of the Ashaft |93 remote from the-timer housing; vSaid remoteend of'the shaft |93 is formedwith an 4enlargement 295 containingbearings20`| supporting the'projectingend of the stem |99, saidprojectingend'carryinga head 299=form ing a hand knob secured tothestem. as by means of one or Amore set screws 2|-|, and enclosing -afriction clutch 2 |'3 comprising a vmember provided with spring pressedpressure elements 2|.5frictionally connecting the clutch member 2|3 withthejhead .209 and hence with the stem |99. Inwardlyv of. thehead1-20.9,l the clutchmember 2|.3 is provided with asleeve vextensionwith a ,center recess constructed loosely to4 embrace the enlargedportion 205 of shaft |93 and such sleeve portion has a driving gear 2|1secured thereto as` by means'of a fastening nut 2 |'9 threadedlyengaging said 'sleeve portion. This gear 2|1 is drivingly connected withthe drive shaft |69 by gears 22| including a driving gear on the driveshaft |69 whereby the stem |99 is driven by the motor 4| and hence intimed relationship with thework piece The purposev of the clutch means2|3 is to allow for changing the angularity of the switch actuating cam|85 with respect to the drive means in order to' adjust the timerquickly and easily.

In order to automatically adjust the timer in accordance with thelongitudinal position of the carriage with respect to the grindingwheel, the shaft |93 on which the switch carrying members |81 and |89are secured is provided with external flutes 223 forming gear teethextending longitudinally of the shaft. .These teeth drivingly engagewith corresponding teeth on a rack member -225 on a slide 221 movable inguideways f 229 formed Vin a plate 23| extending at the side of thecarriage 35 and secured thereto as .by means of the bolts 233. The lowerends of the plate 23| and the slide 221 extend adjacent the wall 55 atthe front of the base 33 and said wall has mounted on it a plate member235 formed with an edge providing a cam surface 23.1. The plate 235 ispivotally mounted on a stud 239 mounted in the wall 55 'and said platemay be provided with an extending arm 24| lforming a convenient handlefor tilting the plate member on its pivot `pin 239 whereby the camsurface 231 may be arranged' at any desired angularity on the frame. Theplate 235 also may bev provided with an arcuate slot 243 through which alocking stud 245 may extend for threaded engagement in a socket formedin the wall 55. By tightening the anchoring stud 245, the plate 235 maybe secured in adjusted position. The slide 221 near its lower endcarries a wheel or roller 241 in position to ride upon the cam surface231. The weight of the rack and slide normally urges the same inadirection to maintain the roller 241 in engagement with the cam surface231 thereby determining the angular position of the shaft |93. As thecarriage 35 is moved in one direction or the other to move the workpiece with respect to the grinding wheel, the plate 23| and the roller241 will move with the carriage along the cam 23.1 and the shaft |93consequently will be turned by the weight of the slide 221 and thedriving connection between the rack 225 and the gear teeth 223 on theshaft. rJfhe amount of turning of the shaft |93 per unit of carriagemovement is, of course, .determined by the slope of the cam surface 231.When said surface is parallel with respect to the carriage guideways 59and 5 l, the shaft |93 will not turn. As the ,inclination of the surface231 with respect to the carriage guideway means is increased, theangular movement of the shaft |93 in response to carriage movement willincrease. By properly adjusting the angularity of the plate 235, themovement of the shaft |93 can be m-ade to correspond exactly with thehelical configuration of the work piece grooves l5. Since the switch |8Iis carried by the shaft |93, Vmovement of the shaft in the mannervdescribed under the control of the cam 231 will automatically advanceor retard the operation of the switch. as a proportional function ofcarriage movement. Consequently, by adjusting the .cam 231, theactuation of th switch |8| may be regulated to cause the magnet tooperate at progressively changing angular intervals during the rotationof the work piece whereby the same may be presented to the grindingwheel in a manner allowing for the grinding thereon of the helical lands2|.

The control of the timer accomplished by inclining the cam surface 231in the direction shown in Fig. 2 of the drawings may be reversed merelyby adjusting the surface 23.1 to an opposite inclination by pushing thehandle 24! down- Wardly. By so doing, the automatic adjustment of thetiming mechanism will take place in reverse thereby enabling the machineto be used with equal facility upon right and left hand twisted drills.

It is thought that the invention and its numerous attendant advantageswill be fully understood from the foregoing description, and it isobvious that numerous changes may be made in the form, construction andarrangement of the several parts without departing from the spirit orscope of the invention, or sacrificing any of its attendant advantages,the form herein disclosed being a preferred embodiment for the purposeof illustrating the invention.

The invention is hereby claimed as follows:

1.'A grinding machine comprising means for supporting and rotating awork piece in grinding position with respect to a grinding member,including a chuck head, a carriage for said head, said carriage beingmovable to traverse the work piece in front of the grinding member,means to reciprocate said carriage, said head being movable on thecarriage in a direction transversely of the direction of movementof thecarriage whereby to project the Work piece grindingly against saidmember, spring means normally holding the head in retracted position, amagnet operable to move thehead against the resistance of the springmeans, adjustable means for limiting the movement of said head, andtimer means for actuating the magnet in timed relation with respect tothe rotation of said work piece whereby said head and work piece will-be moved toward and from said grinding member at timed intervals duringthe rotation of said work piece.

2. A grinding machine as set forth in claimrl wherein said timer isadjustable, means actuated by said carriage during movement thereof toadjust said timer to advance or retard the actuation of the magnet inresponse to traversing movement of said carriage.

3. A-grinding machine as set forth in claim 1 wherein said timer isadjustable, means actuated by said carriage during movement thereof toadjust said timer to advance or retard the actuation of the magnet inresponse totraversing movement of said carriage and means adjustable todetermine the rate of advancement and retardation.

4. The mechanism of the class described, the combination Aof asupporting base, a grinding member carried thereby, a rockable work headcarried thereby, a chuck carried by said head, a spring member co-actingwith said head yieldingly to retain the same in rest position, a magnetoperable upon excitation to rock said head from rest position againstthe resistance of said spring, timing means in circuit with the saidmagnet, means to rotate said chuck and means to actuate said timer toclose the circuit of said magnet in synchronism with the rotation ofsaid chuck.

5. The mechanism ofthe -class'described, the

, member carried thereby, a rockable work combination of a supportingbase, a grinding member carried thereby, a rockable Work head carriedthereby, a chuck carried by said head, a spring member co-acting withsaid head yieldingly to retain the same in rest position, a magnetoperable upon excitation to rock said head from rest position againstthe resistance of said spring, timing means in circuit with the saidmagnet, means to rotate said chuck, means to actuate said timer to closethe circuit of said magnet in synchronism with the rotation of saidchuck, and means to 'advance or retard the actuation of said timer.

6. The mechanism of the class described, the combination of a supportingbase, a grinding member carried thereby,. a rockable work head carriedthereby, a chuck carried by said head, a spring member co-acting withsaid head yieldingly to retain the same in rest position, a magnetoperable upon excitation to rock said head from rest position againstthe resistance of said spring, timing means in circuit with the saidmagnet, means to rotate said chuck, and means to actuate said timer toclose the circuit of said magnet in synchronism with the rotation ofsaid chuck, said timer including -a circuit breaking member, a rotatableshaft carrying said last named member, manual adjusting meansoperatively associated with said shaft for manual advance or retardationof said circuit breaking member.

7. The mechanism of the class described, the combination of a supportingbase, a grinding member carried thereby, a rockable Work head carriedthereby, a chuck carried by said head, a spring member co-acting withsaid head yieldingly to retain the same in rest position, a magnetoperable upon excitation to rock said head from rest position againstthe resistance of said spring, timing means in circuit with the saidmagnet, means to rotate said chuck, and means to actuate said timer toclose the circuit of said magnet in synchronism with the rotation ofsaid chuck, said timer including a circuit breaking memben a rotatableshaft carrying said last named mem-ber, manual adjusting meansoperatively associated with said shaft for manual advance or retardationof said circuit breaking member, means to rotate said shaft, saidadjusting means being yieldingly connected to said shaft rotating means.

8. The mechanism of the class described, the combination of a supportingbase, a grinding head carried thereby, a chuck carried by said head, aspring member co-acting with said head yieldingly to ret-ain the same inres-t position, a magnet operable upon excitation to rock said head fromrest position against the resistance of said spring, timing means incircuit with the said magnet, means to rotate said chuck and means toactuate said timer to close the circuit of said magnet in synchronismwith therotation of said chuck, said timing means comprising normallyclosed contacts in the magnet circuit, a carrying member for saidcontacts, a rotatable circuit breaker operable intermittently toseparate said contacts and open said circuit, a rotatable shaftcarry-ing said circuit breaker, means to rotate the same in synchronismwith said chuck rotating means, a shaft connected to said contactcarrying member and means adjustably to rotate said last named shaft toadvance or retard the circuit breaking action of said circuit breaker.

9. The mechanism of the class described, theA combination of asupporting base, a grinding member carriedV thereby, a rockable Workhead carried thereby, a chuck carried. by said head, a spring memberco-.acting vwith'. said head yieldingly to retain the same inrestposition, a magnet operable upon excitation to rock said head from restposition against the resistance of said spring, timing means in circuitwith thesaid magnet, means to rotate said chuck, land means to actuatesaid timer .to close the circuit of said magnet in synchronism with .therotation of said chuck, said timing means comprising vnormally closedcontacts in the magnet circuit, a carrying member Vfor saidl contacts, arotatable lcircuit breaker operable intermittently to separate saidcontacts4 and open'said circuit, a rotatable shaft carrying said circuitbreaker, means to rotate thepsame in synchronism `Withsaid chuckrotating means, a shaft connected to said contact carrying member andmeans yadjustably to rotate. said last named shaft to advance or retardthe circuit breaking acti-on of'said circuit breaker,.said.last'named:means comprising teeth ,upon said second named shaft and a slidablerack having teeth latching therewith whereby movement'of said rack -willangularly move said second named shaft .and .contact carrying member.

.10.y The mechanism of 4the class described, the combination of a:supporting base, av grinding membercarried thereby, a .rockable .workhead carried thereby, a chuck carried by said head, a spring` member oo-acting withl saidhead yieldingly to` retainthe same in rest position,va magnet operable .upon.-excitation to rock said `head from rest:position vagainst the'resistance of 4said spring, timing means in.circuit `with the said magnet, means .to rotate `said chuck and meansto actuate said timerto close the-circuit ofsaid magnet infsynchronismwith the rotation of said chuck, :said timing means comprising normallyclosed contacts lin theamagnet circuit, ,a carrying. member for saidcontacts, a rotatable circuit breaker .operable intermittently4tofseparate said contacts and-fopensaid circuit, a rotatable shaftcarrying said. circuit breaker, Ameans to rotate thesame -in.synchronisrn with said chuck .rotating means, a shaft .connected tosaid contact carrying member I.and means adjustably to rotate said lastnamed shaft to vadvance or retard the .circuit breaking action I `saidcircuit breaker, said last named means comprising .teeth upon saidsecond-named shaft and a-slidable rackhavingnteeth latchingtherewithwvhereby movement ofV saidv rack will `angularly move saidsecond named shaft yand lcontact carrying. member, a carriage, saidcarriage-beingslidably mountedon saidbase and-.carrying said work headand timing means, -means to move said carriage upon saidbase, rackfoperating means operable to move said rack upon movement of saidcarriage upon its supporting means Yand thereby said contact carrying.member.

11. The mechanism of theclass described, thev combination of a.supporting base, a grinding member carried thereby, a carriage slidablymountedonsaid.base,.a.rockable work head carried thereby, a chuck`carried by said head, a spring member co-acting `with said headyieldingly to .retain the same Ain rest position, a magnet operable uponexcitation to rock said head `from .rest position against the resistanceof saidl spring, timing means incircuit .with the said magnet, mea-ns torotate saidchuckand means to actuatesaidtimer to close the crcuitof saidmagnet Ain synchronism with .the rotation .0f said chuck, said; timingmeans .comprisingmormaliy closedcontactsA in.` thezmagneticircuit,carrying member'v for .saidl ,contacts .ra rotatable .circuit breakeroperable A.intermittently ato -s'eparatexsaid contacts andfopen saidcircuit, a `rotatableshaft carrying said circuit breaker, means torotatesithe same .in ,synchronism' Lwith .said chuck :rotating means, .ashaft iconnectedtztoissaid. :contact :carryfing .member and: means.adjustably tofrrotate .said last inamed. shaft itoeadvance .orretard:the circuit breaking :aCtionLQisaidl circuitibreaker, .saidiflast named.means,comprisingteeth:upon :said second named` shaft. .and :a.sli'dable Track having :teeth latching therewith .whereby .movement of.said rack ;Wil1..angularl'y imovexsaid' secondk named shaft and contactcarrying member, carriage supporting, lmeans,1 Vsaid .carriage .being.-slidably mnuntedthereon, vmeans lto. :move fsaid carriagev upon its.supporting means, .rack'soperating .means operable uponslidingzmovementiof .said icarriage to .moi/'etsaid.rack'iuporrsits.supporting .means .and thereby .said :contact: ycarrying. imernber, 'saidilast named means? .being.adjustal'o'levr :toyary thenrate of .-su.ch.movement..

12..The .mechanismnof .the class..describe,d`, .a base member, agrinding ymember` carriedlthereby, a .carriage slidably mounted ron-said .base member, a Work ,head srockably mounted l upon saidlcarriage, a work. carrying :chuck rotatably mounted. .in saidhead,Ameans .to rock said' head to and. from .its rest position during.rotation :of said chuck and :insynChrOniSm therewith, said last `namedmeans including 'an electro-magnet intermittentlyJ excited, timing:means including contacts in-circuitlwith saidmagnetxand'a circuitbreaker operablepintermittently to separate said' contacts, acontactcarrying member, a-shaft se-y cured to :said circuit breaker, Vmeans vtorotate said shaft --in s ynchronism with said .chuck rotating. means-tomake and :break .the circuit including `said contacts and magnet, loneof the elements otsaid-circuit :breaker being manuallyl adjustable -toadvance-or retard fthe .action .of .said circuit breaker, :and meansactuatable by .said carriage-upon .movement :thereof v.automatically to-advanceor reta-rd the. action of said circuit breaker.

13; The mechanism of zthe-.class described, a baseV gmember, a grinding`member .carried'thereby, a carriage slidaloly .mounted fon .said .basemember, a -Work head l.rockably mounted upon saidl carriage, a .Work.carrying .chuck rotatably mounted in said head,.g,means:to rock saidhead to ,and :from `its :rest .position-during rotation yof said chuck:and in synchronism therewith, said last named means 4including ,an.electro-magnet' intermittently excited; timing means `includingcontacts-.in circuit Lwith said magnetand a circuitbreaker'-operableintermi-ttently .to separate `said contacts, .a contactcarrying zmember, a shaft secured to said circuit breaker, means:=.tovrotate said shaft Y:in ,-synchronism: with said chuck rotating,meanstto :makeiand .break the lcircuit -including. .sai-dv contacts:.and magnet, one fof' ythe elements qof. said circuit breaker being.manually adjustable to. advance or retard :the action of said circuitbreaker, and .means actuatable by said *carriageY upon movement thereofyautomati- Qally 'to adr-ance ori'retard. the action oi saidV circuitbreaker, said last. named means comprising va .cam fsurfaced .memberVcarried by said ibase' and a racki actuatable byv the cam surface Yofsaid member.

14. The mechanism of the class described, -abase 4memhern a :grinding.member i*carried* lthereby, a carriage slidably mounted on said basemember, a work head rockably mounted upon said carriage, a work carryingchuck rotatably mounted in said head, means to rock said head to andfrom its rest position during rotation of said chuck and in synchronismtherewith, said last named means including an electromagnetintermittently excited, timing means including contacts in circuit withsaid magnet and a -circuit breaker operable intermittently to separatesaid contacts, a contact carrying member, a shaft secured to saidcircuit breaker, means to rotate said shaft in synchronism with saidchuck rotating means to make andbreak the circuit including saidcontacts and magnet, one of the elements of said -circuit breaker beingmanually adjustable to advance or retard the action of said circuitbreaker, and means actuatable by said carriage upon movement thereofautomatically to advance or retard the action of said circuit ed to varythe movement of actuation of said rack member.

15. The mechanism of the class described, a base member, a grindingmember carried thereby, a carriage slidably mounted on said base member,a work head rockably mounted upon said carriage, a work carrying chuckrotatably mounted in said head, means to rock said head to and from itsrest position during rotation of said chuck and in synchronismtherewith, said last named means including an electromagnetintermittently excited, timing means including contacts in circuit withsaid magnet and a circuit breaker operable intermittently to separatesaid contacts, a -contact -carrying member, a shaft secured to saidcir-cuit breaker, means to rotate said shaft in synchronism with saidchuck rotating means to make and break the circuit including saidcontacts and magnet, one of the elements of said circuit breaker beingmanually adjustable to advance or retard the action of said circuitbreaker, and means actuatable by said carriage upon movement thereofautomatically to advance or retard the action of said circuit breaker,said last named means comprising a cam surfaced member carried by saidbase and a rack actuatable by the cam surface of said member, said lcamsurface member being adjustably mounted to vary the movement ofactuation of said rack member, said rack member being carried by saidcarriage,

Lal

16. A grinding machine comprising a frame, a

grinding wheel on said frame, a carriage movableon said frametransversely of said wheel, a work head, a chuck carried thereby forsupporting a work piece in grinding position with respect to said wheel,means for rotating said chuck, said work head being tiltable on said`carriage in a direction transversely of the carriage whereby to projectthe work piece carried by said chuck grindingly against the wheel, meansincluding a magnet for so tilting the head, timing means on saidcarriage electrically connected with said magnet and driven in timedrelation with the rotation of the chuck for actuating the magnet, andcam means on the frame and carriage operably connected with said timingmeans for regulating the same progressively in response to carriagemovement on the frame.

17. A grinding machine comprising a frame, a grinding wheel on saidframe, a carriage movable on said frame transversely of said wheel, awork head, a chuck carried thereby for supporting a work piece ingrinding position with respect to said wheel, means for rotating saidchuck, said work head being tiltable on said carriage in a directiontransversely of the carriage whereby to project the work piece carriedby said chuck grindingly against the Wheel, means including a magnet forso tilting the head, timing means on said carriage electricallyconnected with said magnet and driven in timed relation with therotation of the chuck for actuating the magnet, cam means on the frameand carriage operably connected with said timing means for regulating`the same progressively in response to carriage movement on the frame,and means sco-acting with said chuck to reciprocate the same during eachrotation thereof.

WALTER. UMBDENSTOCK.'

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED sTATFev PATENTS

